JP4647828B2 - Scintillator panel and radiation detector using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a scintillator panel used for radiographic imaging and a radiation detector using the scintillator panel, and more particularly to a scintillator panel having a large area and a radiation detector using the scintillator panel.
[0002]
[Prior art]
In the medical and industrial fields, there is an increasing need for radiation detectors that detect and image radiation images quickly and with high accuracy. In order to meet this need, for example, a radiation detector that captures an image corresponding to a radiation image by converting a radiation image into an optical image by a scintillator and capturing an optical image converted by an imaging device is known. .
[0003]
Furthermore, as a radiation detector capable of detecting and capturing a radiation image of a large area, for example, there is a scintillator panel and a radiation detector disclosed in International Publication WO00 / 36436 (hereinafter referred to as Reference 1). . This scintillator panel has a large area by arranging optical fiber plates (FOP) side by side, and a scintillator panel having a large area is formed by depositing the scintillator there.
[0004]
[Problems to be solved by the invention]
In order to form a scintillator panel having a larger area, a method of arranging FOPs in two dimensions can be considered. However, the present inventors have found that the following problems occur simply by arranging in two dimensions. When FOPs are arranged two-dimensionally and their side surfaces are bonded together with an adhesive, when the surface of the large area plate is polished, the adhesive is scraped due to the hardness difference between the FOP and the adhesive. The step becomes large. For this reason, if a chip exists in one of the four corners adjacent to the FOP, the adhesive portion becomes large, and the center portion becomes thin during polishing, resulting in a decrease in adhesive strength. Furthermore, the adhesion strength of the scintillator formed on the upper part also decreases.
[0005]
Therefore, the present invention provides a scintillator panel that can suppress a decrease in the adhesion strength of the scintillator to the bonded portion of the FOP panel in a scintillator panel using an FOP panel formed by arranging FOPs in two dimensions and adhering the side surfaces with an adhesive. It is another object of the present invention to provide a radiation detector using the same.
[0006]
In order to solve the above problems, the scintillator panel according to the present invention forms a plurality of optical fiber plates formed by bundling a large number of optical fibers, and forms a planar input / output end surface by bonding the side surfaces thereof with an adhesive. In a scintillator panel formed by depositing a scintillator that emits light having a wavelength that can be transmitted through an optical fiber upon incidence of radiation on the input end face, the input / output end face has at least two optical fiber plates in the side direction of the optical fiber. The corners of the optical fiber plate are bonded to the sides of the other optical fiber plate except for the edges of the input / output end faces, and the scintillator is formed as a columnar crystal by vapor phase growth. It is characterized by being. The optical fiber plate is preferably rectangular.
[0007]
In this way, the corner portion is bonded to the side portion of the other optical fiber, and the corner portions of the respective plates are arranged as far as possible so that the width of the adhesive layer does not become too large around the corner portion. The above-mentioned problem can be solved.
[0008]
Scintillator, visible by X-ray incidence, which emits ultraviolet light or infrared light, for example, it is preferable can those containing CsI is used various existing imaging device as an imaging device.
[0009]
The adhesive is preferably a material that absorbs 50% or more of the light emitted from the scintillator. The adhesive is formed on the side surface of the optical fiber plate constituting the side surface of the scintillator panel, and has a transmittance for the light emitted from the scintillator. It is preferable to further include a light shielding material that is less than 50%. If it does in this way, generation | occurrence | production of the noise by propagation of unnecessary incident light can be suppressed.
[0010]
The width of the adhesive is preferably 50 μm or less, and more preferably 20 μm or less. By reducing the width of the adhesive in this way, it is possible to effectively prevent the scintillator from peeling off.
[0011]
It is preferable to further include a protective film covering the scintillator. For example, a moisture-resistant protective film made of polyparaxylylene is suitable.
[0012]
A radiation detector according to the present invention includes the scintillator panel according to the present invention and an imaging device disposed to face the output end face. An optical member for light guide that is disposed between the scintillator panel and the imaging device and guides an optical image output from the scintillator panel to the imaging device may be further provided.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same reference numerals are given to the same components in the drawings as much as possible, and duplicate descriptions are omitted. In addition, the dimension and shape in each drawing are not necessarily the same as an actual thing, and there exists a part exaggerated and drawn for easy understanding.
[0014]
FIG. 1 is an exploded perspective view showing a first embodiment of a scintillator panel according to the present invention, FIG. 2 is a partially enlarged sectional view thereof, and FIG. 3 is an enlarged view of a corner bonding portion of the FOP. It is.
[0015]
The scintillator panel 1 has a configuration in which the scintillator 3 is deposited on the FOP panel 2 formed by arranging a plurality of FOPs 20 two-dimensionally and the side surfaces thereof are bonded together with an adhesive 21, and the scintillator 3 is covered with a protective film 4.
[0016]
Here, each of the FOP 20 constituting the FOP panel 2 a rectangular shape, the length of the short sides is the same for both a, FOP 20 ₁ and the long side length the length of the long side is b is there only long FOP 20 ₂ of the two FOP c than that. Then, as shown in FIG. 1, connects the FOP 20 ₁ and FOP 20 ₂ in the long side direction, in the short side direction, the FOP 20 ₂ next to the FOP 20 _1, are alternately arranged FOP 20 ₁ next to the FOP 20 ₂ ing. As a result, although adjacent to the FOP 20 ₁ and FOP 20 ₂ of each corner portion 20 ₁ c, 20 ₂ c adjacent to the long side direction, FOP 20 ₂ of side portions of these corners is adjacent to the short side direction 20 ₂ Since it faces s, it can prevent that the width | variety of the adhesive agent 21 layer formed between these expands large compared with another part.
[0017]
Here, as the adhesive 21, it is preferable to use a material capable of suppressing the light transmittance between the end faces to less than 50%. In the case where the core of the optical fiber constituting the FOP 20 is exposed at the end face, if the light transmittance of the adhesive 21 is large, leakage from the core or disturbance light to the core via the adhesive 21 Can be suppressed, and mixing of noise into the obtained optical image can be suppressed. As such an adhesive 21, trade name EPO-TEK 353ND manufactured by Epoxy technology in the USA is suitable. If the adhesive 21 is colored, visual inspection at the time of manufacturing the FOP panel 2 is facilitated, which is preferable.
[0018]
As described in Reference 1, the width W of the adhesive 21 layer is preferably 50 μm or less, and more preferably 20 μm or less. More preferably, the distance r from the opposite side at the edge is preferably 50 μm or less, and more preferably 20 μm or less. By setting in this way, it is possible to prevent the scintillator 3 from peeling and to obtain a high yield. In this embodiment, since the arrangement of the FOP 20 is devised as described above, it is not necessary to set the width W extremely narrower than the preferable limit of 50 μm or 20 μm in order to keep the interval r within a preferable range. The manufacture becomes easy.
[0019]
A light shielding material 22 is formed on the exposed side surface of the FOP panel 2 by coating. The light shielding material 22 has a light transmittance of less than 50%, and disturbing light or the like is prevented from entering the core of the optical fiber constituting the FOP panel 2 through the light shielding material 22. There is an effect of suppressing the mixing of noise into the optical image.
[0020]
As the scintillator 3, various materials that emit predetermined light (including visible light, infrared light, and ultraviolet light) according to incident radiation can be used, but Tl-doped CsI with high luminous efficiency. Etc. are preferred. It is preferable to form the scintillator 3 by vapor phase growth because a homogeneous scintillator can be formed even in a large area. Then, as shown in FIG. 2, it is more preferable to form a columnar structure because an organic film 41 of a protective film 4 described later enters between the columnar structures, and the adhesion of the organic film 41 is improved. The thickness of the scintillator 3 is preferably about 600 μm.
[0021]
A protective film 4 that covers the scintillator 3 and reaches the side surface of the FOP panel 2 is formed. The protective film 4 is formed with, for example, a three-layer structure of an organic film 41, an inorganic film 42, and an organic film 43, and has a function of blocking water vapor with X-ray permeability. As the organic films 41 and 43, for example, polyparaxylylene resin (manufactured by Three Bond, trade name Parylene), particularly polyparachloroxylylene (trade name, Parylene C) is preferably used. The coating film made of parylene has very little water vapor and gas permeation, has high water repellency and chemical resistance, has excellent electrical insulation even in a thin film, and is transparent to radiation and visible light. It has excellent characteristics suitable for use in As the inorganic film 42, it is preferable to use a metal thin film that is X-ray transparent and reflects light emitted from the scintillator 3, for example, a metal thin film such as Al, Ag, or Au.
[0022]
When the scintillator 3 itself has sufficient moisture resistance and durability, the protective film 4 is not necessary, but when using a material having deliquescence such as CsI, for example, the moisture resistant protective film is essential. The protective film 4 can be composed of only the organic film 41 as the simplest structure. In the present embodiment, the protective film 4 has a three-layer structure to improve its sealing property and moisture resistance, and by using the light-reflective inorganic film 42, the light emitted from the scintillator 3 can be effectively emitted. This leads to an effect of improving luminous efficiency and obtaining a bright image. In addition, sandwiching the inorganic film 42 between the organic films 41 and 43 also has an effect of preventing the deterioration of the inorganic film 42.
[0023]
In this embodiment, the organic film 41 is formed so as to secure a height of about 10 μm from the re-top portion of the columnar crystal of the scintillator 3, and the inorganic film 42 is a thin film of about 0.25 μm, and further about 10 μm. An organic film 43 having a thickness of 5 mm is formed.
[0024]
When radiation that forms a radiation image is incident from the incident surface side of the scintillator panel 1, that is, the protective film 4 side, the incident radiation passes through the protective film 4 and is guided to the scintillator 4. The scintillator 4 converts the radiation image into a visible light image by generating visible light according to the amount of incident radiation. The converted visible light image is output from the opposite surface via the FOP panel 2. Here, by disposing the light-reflective inorganic film 42 in the protective film 4, the inorganic film 42 is generated by the scintillator 4 and reflects the visible light going back to the incident surface side to reflect the FOP panel 2 side. Leads to a bright visible light image.
[0025]
According to the present invention, since the distance r of the adhesive 21 between the FOPs 20 can be easily set short by devising the arrangement of the FOPs 20 as described above, the scintillator 3 is not peeled off and the dead space is eliminated. Can be set narrowly, and it is easy to enlarge the screen.
[0026]
By arranging a solid-state imaging device such as a photographic film, a TV camera, a CCD, or a MOS on the output end face side, a visible light image corresponding to a radiation image can be recorded. FIG. 4A is a cross-sectional configuration diagram of the radiation detector 9 using the scintillator 1.
[0027]
As shown in FIG. 4 (a), the radiation detector 9 connects the input end face of the light guiding fiber optical block 5 to the output end face of the scintillator panel 1 shown in FIG. The solid-state imaging device 6 is disposed on the output end face.
[0028]
Each fiber optical block 5 has a tapered configuration in which the input end face is wider than the output end face, and thus has a function of reducing and outputting the input image. Therefore, in order to generate an image image corresponding to the original radiographic image, it is necessary to perform image processing for enlarging and rearranging an image captured by each solid-state imaging device 6 by a processing device or the like (not shown). By adopting such a configuration, it is possible to capture a large-screen radiation image without using a large-screen image sensor. When a large solid-state image sensor 6 can be used, as shown in FIG. 4B, the light-receiving surface of the solid-state image sensor 6 directly on the output end face of the scintillator panel 1 shown in FIG. May be pasted together.
[0029]
The arrangement of the FOP 20 in the FOP panel 2 constituting the scintillator panel 1 according to the present invention is not limited to the arrangement shown in FIG. For example, like the FOP panel 2a shown in FIG. 5, FOPs 20 ₃ , 20 ₄ , and 20 ₅ having different widths from a ₁ , a ₂ , and a ₃ may be combined, and the FOP panel 2b shown in FIG. In this manner, rectangular FOPs 20 ₇ having a short side length b / 2 and a long side length b are alternately arranged around a square FOP 20 ₆ having a side length b / 2. good. Further, the rectangular FOPs 20 ₇ may be alternately arranged to form an FOP panel 2c as shown in FIG. Further, the FOP panel 2d having a larger screen as shown in FIG. 8 may be formed by connecting FOPs 20 ₈ and 20 ₉ having different widths to the FOP panel 2 shown in FIG.
[0030]
The FOP for forming the scintillator panel according to the present invention is not limited to the rectangular shape (including the square shape) described above, but is combined with _a parallelogram-shaped FOP 20 _a as shown in FIG. or forming a FOP panel 2e, it is also possible to configure the FOP panel 2f in combination FOP 20 _b of the trapezoidal as shown in FIG. 10. The same applies to the case of combining polygonal FOPs having a larger number of sides or FOPs having different shapes. In any case, by bonding the corners of two FOPs with the sides of other FOPs, the width of the bonding part can be reduced, the strength can be ensured, and the scintillator can be prevented from being peeled off. Secure yield.
[0031]
【The invention's effect】
As described above, according to the present invention, when the FOP panel constituting the scintillator panel is created, the corners of any two FOPs among the plurality of FOPs constituting the scintillator panel are arranged on the sides of the other FOPs. By adhering, the width of the bonding portion can be reduced, the strength can be ensured and the peeling of the scintillator can be suppressed, and a stable yield can be ensured.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a first embodiment of a scintillator panel according to the present invention.
FIG. 2 is a partially enlarged cross-sectional view of FIG.
FIG. 3 is an enlarged view of a corner bonding portion of the FOP of FIG. 1;
4 is a cross-sectional view showing a radiation detector according to the present invention using the scintillator panel of FIG. 1; FIG.
FIG. 5 is a perspective view showing an FOP arrangement in a second embodiment of a scintillator panel according to the present invention.
FIG. 6 is a perspective view showing an FOP arrangement in a third embodiment of a scintillator panel according to the present invention.
FIG. 7 is a perspective view showing an FOP arrangement in a fourth embodiment of a scintillator panel according to the present invention.
FIG. 8 is a perspective view showing an FOP arrangement in a fifth embodiment of a scintillator panel according to the present invention.
FIG. 9 is a perspective view showing an FOP arrangement in a sixth embodiment of a scintillator panel according to the present invention.
FIG. 10 is a perspective view showing an FOP arrangement in a seventh embodiment of a scintillator panel according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Scintillator panel, 2 ... FOP panel, 3 ... Scintillator, 4 ... Protective film, 5 ... Fiber optical block, 6 ... Solid-state image sensor, 9 ... Radiation detector, 20 ... FOP, 21 ... Adhesive, 22 ... Light shielding material 41, 43 ... an organic film, 42 ... an inorganic film.

Claims (12)

A plurality of optical fiber plates formed by bundling a large number of optical fibers can be bonded to each other with an adhesive to form planar input / output end faces, and the optical fibers can be transmitted through the input end faces by incidence of radiation. In a scintillator panel formed by depositing scintillators that emit light of a wavelength,
The input / output end face is configured by arranging at least two or more optical fiber plates in the side direction of the optical fiber, and the corner of the optical fiber plate except for the edge of the input / output end face is another light. A scintillator panel , wherein the scintillator is bonded to a side of a fiber plate and the scintillator is formed as a columnar crystal by vapor phase growth .   The scintillator panel according to claim 1, wherein the optical fiber plate has a rectangular shape. The scintillator The scintillator panel according to claim 1 or 2, characterized in that to emit visible light, ultraviolet light or infrared light by X-ray incidence. The scintillator panel according to claim 3 , wherein the scintillator includes CsI. The scintillator panel according to any one of claims 1 to 4 , wherein the adhesive is a material that absorbs 50% or more of light emitted from the scintillator. The light-shielding material which is formed on the optical fiber plate side surface which comprises the side surface of the said scintillator panel, and has the transmittance | permeability with respect to the light radiated | emitted from the said scintillator is further provided in any one of Claims 1-5. The scintillator panel described. The scintillator panel according to any one of claims 1 to 6, wherein the width of the adhesive is 50μm or less. The scintillator panel according to claim 7 , wherein the adhesive has a width of 20 μm or less. The scintillator panel according to any one of claims 1 to 8, characterized in that it further comprises a protective film covering the scintillator. The scintillator panel according to claim 9 , wherein the protective film includes a moisture-resistant protective film made of polyparaxylylenes. A radiation detector, characterized in that it comprises a scintillator panel according, and an imaging device which is disposed opposite to the output end face to claim 1-10. Wherein disposed between the scintillator panel and the imaging device, according to claim 11, characterized in that it comprises an optical image output from the scintillator panel further an optical member for guiding the light guided to the image pickup device Radiation detector.

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